This invention relates to a method and apparatus for interpreting publication data. More particularly, the invention is directed to a method and system for processing comments, which are created in an open specification system, that relate to objects in the publication data. It will be appreciated, however, that the invention is also amenable to other like applications.
Documents displayed on a processing device (e.g., computer) are typically converted to a Page Description Language (PDL), such as Postscript or PDF, before being printed. Page layout applications (e.g., PageMaker) are often used to create these documents, and to insert and manipulate high-resolution, data intensive images. Since the data is typically voluminous, such images cannot be easily manipulated (magnified, rotated, etc.) on-the-fly. Therefore, with the Postscript and PDF PDLs, a method (e.g., “Open Prepress Interface” (hereinafter abbreviated to “OPI”)) has been employed in which the high-resolution image data portion of the document is stored in respective files, possibly at locations remote from the client computer. Corresponding low-resolution images are created and possibly stored at separate locations from the high-resolution images. These low-resolution images, or “proxy” images, are then inserted in the document, along with references to the high-resolution versions. Because the low-resolution image utilizes substantially less data, it is possible for a user to manipulate such images significantly faster, and using less of the client computer's resources (disk space, memory, processor time), than a corresponding high-resolution image. For each proxy image inserted in the document, a set of comments is created, conforming to the OPI specification; these comments reference the location of the high resolution image, as well as indicating any manipulations made to the proxy image, which must be made to the corresponding high-resolution image before it is printed. The software which generates the proxy image and OPI comments can be referred to as an OPI producer, and may be either part of an OPI package or a page layout application.
When it is desirable to print the document, including the high resolution versions of inserted images, produced with page layout applications utilizing OPI, the document is converted to the PDL, which is transmitted to a server or series of servers for print processing. A print processing device decomposes the PDL data according to a raster image processing (RIP) technique, which translates the Postscript data into bits. The device which performs this activity will hereinafter be referred to as a RIP server. Either prior to RIP or on-the-fly during RIP, the same or another device interprets the OPI comments in the PDL, retrieving and substituting the high-resolution image data, and modifying the data to reflect the manipulations made by the user to the proxy image.
Heretofore, the OPI software packages store and retrieve both the high-resolution and low-resolution image data. Because the conventional OPI packages perform the storage operations, the locations of the high and low-resolution image data are known. Therefore, retrieving that data to perform the print operations is easily achieved. Until now, it has not been possible to reliably locate the high and low-resolution image data using an OPI package that was not used to store the data.
The present invention provides a new and improved apparatus and method that overcomes the above-referenced problem and others.